We are studying certain immunological features in patients with flammatory bowel disease (IBD) which we hope will give us insight into possible pathogenic mechanisms. Specifically, we are examining cells of the lymphoid series which are involved in regulation of immune function in a suppressive fashion. We believe these suppressor T-lymphocytes may not function adequately, allowing unchecked and damaging immune reactions to take place. We are using various techniques, including Concanavalin A-induced suppressor cells to study these phenomena. Additionally, we are studying the macrophage of patients with IBD, since this cell may also perform certain immune regulation. Our experiments also include examination of the lymphocytes of the lamina propria of intestine of patients with IBD and are aimed at determining if these lymphocytes can mediate a variety of cytotoxic reactions which could damage the intestine. Finally, we are attempting to study experimentally induced granulomas in mice, determine what cells are important in this production and attempt to suppress this formation using a variety of techniques.